Health

Fat Mass vs Lean Mass

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Body composition reference values come from large population studies (NHANES, WHO). They provide a framework for interpreting your results, but your personal health context always takes priority. This calculator determines your fat mass and lean mass percentages. Data updated to 2026 and reviewed regularly to keep you current.

Last reviewed: May 12, 2026 Verified by Hacé Cuentas Team Source: NIST — National Institute of Standards and Technology, Khan Academy, Wolfram MathWorld 100% private

When to use this calculator

  • Technical calculations for body composition tracking
  • Fitness professionals and health students
  • Validate body composition estimates before applying them
  • Understanding and teaching body composition concepts
  • Quick reference for fitness and nutrition projects

Sample Calculation

  1. 75 kg at 20% body fat
  2. 15 kg fat mass
Result: 60 kg lean mass

How it works

1 min read

Your body composition reference values come from large population studies (NHANES, WHO, CDC). They vary by age, sex, ethnicity, and region. Use these as guidelines—your personal medical history always takes precedence.

How It's Calculated

Body composition is the breakdown of your body weight into fat mass and lean mass.

This calculator applies the formula with your inputs, checking ranges and alerting you if values fall outside normal ranges.

Normal Reference Values for Adults

MetricNormal Range
Blood Pressure<120/80 mmHg
Resting Heart Rate60-100 bpm
Body Temperature36.1-37.2°C
Blood Oxygen (SpO2)95-100%
Fasting Blood Sugar70-100 mg/dL
HbA1c<5.7%
Total Cholesterol<200 mg/dL
LDL Cholesterol<100 mg/dL
HDL Cholesterol>40 (M) / >50 (F)

Final Notes

This calculation is a reference guide only. For critical decisions (medical, financial, legal), consult a qualified healthcare professional. Values are updated to 2026 and reviewed regularly.

Frequently asked questions

What is a healthy body fat percentage?

Men: 10-20%. Women: 18-28%. These ranges support normal health and hormonal function.

How do you measure body fat percentage?

Methods include bioimpedance (Tanita scales), DEXA scans (gold standard), and calipers (skinfold measurement).

What does lean mass include?

Lean mass includes muscle, bone, water, organs, and connective tissue—everything that isn't fat.

How do I lose body fat?

Create a calorie deficit of 300-500 kcal/day. Combine cardio with strength training for best results.

How do I build muscle mass?

Eat a calorie surplus of 200-400 kcal/day with 1.6-2.2 g protein per kg body weight.

Why do women need more body fat than men?

Women require higher body fat for hormonal health and menstruation. Below 14% becomes critical.

What body fat percentage is unhealthy for men?

Below 6% is not sustainable for long-term health and can cause serious metabolic issues.

When should I see a doctor about my body composition?

Consult a healthcare provider if your values fall outside normal ranges, you have associated symptoms, or have a family history of cardiovascular or metabolic disease.

Sources and references